Data Processing, Feature Extraction, and Time-Series Analysis of Sentinel-1 Synthetic Aperture Radar (SAR) Imagery: Examples from Damghan and Bajestan Playa (Iran)

With the Sentinel-1 satellites of the Copernicus Mission of the European Space Agency a new C-Band Synthetic Aperture Radar (SAR) system operates and acquires data suited for continued earth observation. The so called Interferometric Wide Swath mode realizes a high spatial resolution of less than fifteen meters and offers a large swath width of about 250 km and therefore overcomes existing limitations. The Sentinel-1 Mission offers the opportunity to extensively investigate the temporal and spatial dimension of surface alterations and to recognize, quantify and monitor changes related to active morphodynamics; preferably in arid and semi-arid regions where the influence of volume and random scattering processes on the SAR signal are minimized. With a focused operation time of more than one decade, the Sentinel-1 Mission has potential to essentially contribute to an increased understanding of earth's dynamic processes. The contribution highlights the processing and application of Sentinel-1 data in time series analyses via the terrain corrected gamma nought intensity and the interferometric coherence for the investigation period from March 2015 to January 2017 in the surroundings of Damghan Playa and Bajestan Playa, Iran. Both SAR features showed to be sensitive to the state and dynamic of the arid land surface. Especially the standard deviation of the temporal dimension of both features revealed as suited indicator when assessing the distribution and magnitude of active dynamics. The approach is therefore promising for the monitoring and characterization of morphodynamic events. However, further validation - including the comparison to in situ collected data - is necessary. As well, transferability to other arid, semi-arid and semi-humid sites must be investigated in future research, along with the general constrains that arise from the SAR acquisition, e.g. geometric distortions, or speckle. Finally, future work must address questions on the size and magnitude of detectable events and the land surface parameters that predominantly alter the signal.